1. Field of Invention
The present invention relates to the technical field of oil field coiled tubing operation, and in particular, to a dedicated coiled tubing guide-in tool, namely, a coiled tubing guide-in device, capable of pulling a coiled tubing out of a tubing reel and guiding the coiled tubing into injector head gripper blocks.
2. Related Art
Currently, a coiled tubing unit is dedicated equipment used for oil-gas well operation, which mainly consists of a tubing reel (coiling coiled tubing), an injector head (which clamps the coiled tubing through the gripper blocks and injects the coiled tubing into the oil-gas well or lifts the coiled tubing out of the oil-gas well), and a power control system. During an installation process of the device at the well site, the coiled tubing on the tubing reel must be pulled out and inserted into the injector head gripper blocks before the subsequent installation operations are performed. However, before the coiled tubing pulled out of the tubing reel is put into an injector head guider, the coiled tubing must be straightened through an external force, and before the coiled tubing enters the injector head gripper blocks through the gooseneck guider, the coiled tubing is bended along with an are surface of the gooseneck guider. After that, the coiled tubing is inserted in the injector head gripper blocks.
Currently, two common methods are used. One method is a snake-rope coiled tubing guide-in device, in which a steel wire rope (referred to as a snake in other countries) with a radius being the same as that of an external radius of the coiled tubing is used. On end of the steel wire rope is connected to the coiled tubing on the reel through a special joint, and the other end is inserted in the injector head gripper blocks. An injector head motor is then started to guide the steel wire rope into the injector head. Finally, the coiled tubing is guided into the injector head, the steel wire rope and the joint are sawed from the coiled tubing, and the snake-rope guide-in device is dismounted, thereby completing the guide-in process of the coiled tubing. Such a steel wire rope guide-in tool has a firm joint connection, the strength thereof is well beyond the use requirement, and the rigidity is also appropriate. Therefore, the tool is safe to use. The deficiency thereof lies in that, after the coiled tubing is guided into the injector head, the snake-rope guide-in device cannot be taken down until the connection joint and the coiled tubing head are cut off, which wastes the expensive coiled tubing and causes inconvenience in use. In addition, for a coiled tubing with a great diameter (the diameter above 2⅜″), such a snake-rope guide-in device provides poor flexibility in operation, which directly affects the pipe guide efficiency. In ordinary operation well sites, it is generally required that a distance from the injector head to the tubing reel be greater than 10 m. As a result, the weight of the guide-in device, which uses solid steel as a main material, is increased dramatically. The guide-in device becomes clumsy, increases the labor intensity of workers, and is inconvenient to operate. The second method is a winch coiled tubing guide-in device. The operation principle is as follows: a thin steel wire rope with sufficient strength is used, an end thereof passes through gripper blocks and is fixed on the coiled tubing through a joint, and the other end passes through a blow-out preventer and is fixed on a winch. The winch is rotated through an external power source, so as to pull out the coiled tubing and finally guide the coiled tubing out of the stuffing box, thereby releasing the guide-in tool. The winch coiled tubing guide-in device provides desirable flexibility and reduces the labor intensity of workers, however, it requires an external power source and is inconvenient to use on site.